生成一份树莓派4B用opencv和dlib进行闭眼检测，闭眼超过五秒蜂鸣器会响，摄像头是连接树莓派的usb摄像头，视频在电脑上显示的代码

好的，我理解了你的要求。你需要在树莓派4B上使用opencv和dlib进行闭眼检测，如果闭眼超过五秒钟，蜂鸣器会响起，同时使用USB摄像头进行检测，并在电脑上显示视频。以下是实现该功能的代码：

import cv2
import dlib
import time
import RPi.GPIO as GPIO

# 设置蜂鸣器引脚
buzzer_pin = 18
GPIO.setmode(GPIO.BCM)
GPIO.setup(buzzer_pin, GPIO.OUT)

# 加载面部关键点检测器和眼睛检测器
detector = dlib.get_frontal_face_detector()
predictor = dlib.shape_predictor("shape_predictor_68_face_landmarks.dat")

# 设置视频捕获对象
cap = cv2.VideoCapture(0)

# 定义函数，检测眼睛是否闭上
def is_eyes_closed(eye_points, facial_landmarks):
    left_eye = facial_landmarks.part(eye_points[0])
    right_eye = facial_landmarks.part(eye_points[1])
    eye_ratio = (left_eye.dist(right_eye) / ((left_eye.x - right_eye.x) ** 2 + (left_eye.y - right_eye.y) ** 2) ** 0.5)
    return eye_ratio < 0.2

# 定义变量，记录闭眼时间
closed_time = 0

# 开始循环检测
while True:
    ret, frame = cap.read()
    if not ret:
        break

    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    faces = detector(gray)

    for face in faces:
        landmarks = predictor(gray, face)

        left_eye_closed = is_eyes_closed([36, 37, 38, 39, 40, 41], landmarks)
        right_eye_closed = is_eyes_closed([42, 43, 44, 45, 46, 47], landmarks)

        if left_eye_closed and right_eye_closed:
            closed_time += 1
        else:
            closed_time = 0

        if closed_time > 5:
            GPIO.output(buzzer_pin, GPIO.HIGH)
        else:
            GPIO.output(buzzer_pin, GPIO.LOW)

        for n in range(36, 48):
            x = landmarks.part(n).x
            y = landmarks.part(n).y
            cv2.circle(frame, (x, y), 2, (255, 0, 0), -1)

    cv2.imshow("frame", frame)

    if cv2.waitKey(1) == ord("q"):
        break

cap.release()
GPIO.cleanup()
cv2.destroyAllWindows()

这段代码使用dlib进行面部关键点检测，检测眼睛是否闭上。如果眼睛闭上超过五秒钟，蜂鸣器就会响起。同时，使用opencv捕获摄像头视频，并在电脑上显示。请注意，你需要下载shape_predictor_68_face_landmarks.dat文件并将其放置在与代码文件相同的目录下，以便运行该代码。